The undo:__ Head off the next-day hangover with plenty of water while you're still at the party (8 ounces of water for every cocktail you consume is ideal—and, honestly, it's best to try to stop at two!). Then, when you get home, chug an electrolyte-filled sports drink or coconut water. When you wake up, have a plate of eggs (which have amino acids that help banish alcohol-related toxins) or a bowl of miso soup (which has plenty of water, sodium, and even some good-for-you bacteria that can help boost your body's ability to rehydrate). You can even try some omega-3 supplements, which can help quell inflammation caused by alcohol.

__The oops: You ate too much.

The undo:__ Get thee to a cardio class! Research has shown that exercise can immediately help your blood vessels relax—which, in turn, can aid in circulation and heart health. A good breakfast—filled with proteins and complex carbs—can help too, so head for oatmeal with berries or whole-wheat toast with eggs.

The undo:__ As challenging as it is, it's best to get up on time. Ouch, I know. But oversleeping will throw off your sleep clock and make it harder to get rest in the upcoming days. Lack of sleep can make you overeat, so stick to filling foods, like whole grains and popcorn, and resist the temptation to sneak in a nap. Instead, head to bed about an hour earlier than you normally would.

__The oops: You shared germs with a double-dipper.

The undo:__ The results from one study showed that double-dipping a chip—you know, dipping, tasting, then dipping again—three to six times can transfer about 10,000 microbes from the mouth back to the dip. (Um, ew?) So try to keep from touching your nose or mouth, and give your hands a nice, soapy scrub when you're home after the party. (P.S. If you've gotten your flu shot, it reduces your chances of getting sick by about 70 percent.)

__The oops: You wore bad shoes.

The undo:__Well, I'm sure the shoes were probably cute, but standing in them for hours on end may not have done your feet any favors. During the party, make sure to circulate—blood pooling in the legs from standing too long can cause pain and swelling. Stretch out your hamstrings and calves midparty (it's OK to head to the restroom to do this!), and, the next day, elevate your feet and do more leg stretches: Stand up, keep your legs together, and bend forward at the waist to stretch the back leg muscle.

How is your holiday-party circuit going this season? What are your healthy holiday-party tips?